Here I am presenting a wonderful mix of security softwares (free!! :)) to protect your windows based PC.
- AntiVirus: Avira Antivir Personal Edition Classic
- Firewall: Sunbelt Personal Firewall
- Anti Spyware: Spybot
- Sandbox Software: A sandbox software runs all programs you want in a virtual box and prevents malicious programs being downloaded on the fly. I will recommend SandBoxie. Try to run your browser and all IM applications sandboxed.